Field of the Invention
The present invention relates to a light controlling apparatus and a transparent display device, and more particularly, to a light controlling apparatus and a transparent display device having a transparent mode and a light-shielding mode.
Discussion of the Related Art
Recently, with the advancement of the information age, display devices for processing and displaying a large amount of information have been developed. More particularly, various display devices have been introduced and spotlighted. Examples of display devices include liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, electroluminescence display (ELD) devices, and organic electroluminescent display (OLED) devices. The display devices generally have properties of a thin profile, light weight and low power consumption. Thus, their fields of application have continuously increased. In particular, in most electronic devices or mobile devices, a display device has been used as a user interface.
Also, transparent display devices, through which a user may see objects or images located at an opposite side, have been developed. The transparent display devices may have advantages of better use of space, interior and design, and may be applied in various application fields. The transparent display devices may solve spatial and temporal restrictions of the existing electronic devices by realizing functions of information recognition, information processing, and information display as a transparent electronic device. Such transparent display devices may be used for a smart window, which may be used as a window of a smart home or a smart car.
Of the transparent display devices, the transparent display device based on LCD may be realized by applying an edge type backlight thereto. However, the transparent display device to which LCD technologies are applied has a problem in that transparency is deteriorated by a polarizing plate used for realization of black. Also, a problem occurs in outdoor visibility of the transparent display device based on LCD.
The transparent display device based on OLED has power consumption higher than that of the LCD and has a difficulty in displaying a true black. Also, although the transparent display device based on OLED has no problem regarding contrast ratio in a dark environment, a problem occurs in that a contrast ratio is deteriorated under a normal lighting environment.
To solve the above problems, a method for applying a light controlling apparatus to a transparent display device has been suggested, wherein the light controlling apparatus may realize a transparent mode that transmits light incident upon a rear surface of the transparent display device and a light-shielding mode shielding the light. A reflective liquid crystal display device and a method for controlling the same are disclosed in Korean Patent Application No. 10-2011-0103726.